A popular method for administering anesthesia and respiratory gases to a patient is by use of a face mask, which itself is fluidly coupled to other components of an anesthesia or respiratory system. The anesthesia or respiratory system typically includes a gas source, such as an oxygen canister for respiratory purposes, or anesthetic gas canister for the administration of anesthetic gases. A flow control device such as an anesthesia machine is disposed downstream of the gas storage canister for controlling the flow of gas to a patient. A breathing circuit fluidly couples the anesthesia/respiratory machine to the face mask, and includes a proximal end that is mechanically coupled to the anesthesia or respiratory machine, and a distal end that is mechanically coupled to the face mask.
Breathing circuits can be “one-way” circuits that only direct the anesthesia gas or respiratory gas to a patient; or alternately, can be dual circuits that include an inspiratory passage for conducting fresh and/or processed re-breathing gases from the anesthesia machine to the patient, and an expiratory gas passageway for conducting exhaled gases away from the patient.
Examples of breathing circuits, and the anesthesia machines to which they are attached are shown in Fukunaga et al, U.S. Pat. Nos. 6,439,231; 6,003,511; 5,983,896; 5,778,872 and 4,265,235. Additional examples of breathing circuits can be seen in Leagre and Burrow, U.S. Pat. No. 5,404,873; and U.S. Pat. Nos. 3,856,051; 3,556,097; 4,007,737; 4,188,946; 4,265,235; 4,463,755; 4,232,667; 4,596,246; 5,121,746; 5,284,160; 5,778,872; and 6,129,082. A good review of a variety of popular anesthesia circuit types can be found in Fukunaga et al., Published U.S. Patent Application No. US/2003/0183232 A1, that was published on 2 Oct. 2003.
As alluded to above, the face mask includes a connector that defines a gas port. The connector is typically coupled to the proximal end of a breathing circuit. The face mask is placed over the patient's face to cover the patient's nose and/or mouth, so that anesthesia gases may be delivered to the patient without intubation.
Many examples of anesthesia-type face masks exist. For example, various anesthesia face masks can be seen in the patent literature in Keener et al., U.S. Pat. No. 3,815,596; Dahlstrand, U.S. Pat. No. 5,462,050; Hoftman, U.S. Pat. No. 5,738,094; Hellings, U.S. Pat. No. 5,975,079; Hoftman, U.S. Pat. No. 6,035,852; Barnett et al., U.S. Pat. No. 6,412,488; Wix, U.S. Pat. No. 6,736,139; and Kumar, U.S. Pat. No. 6,792,943. Examples of breathing masks are also shown in many of the breathing circuit-related patents discussed.
In addition to the patent literature, several types of commercially available face masks exist. Among these masks are masks that are manufactured or distributed by companies such as Narang Medical, Ltd. (See www.narang.com); Mainline Medical (See www.mainlinemedical.com); Keomed, Inc. (See www.keomed.com); and VitalSigns, Inc. (See www.vital-signs.com). Additionally, the Assignee of the present invention, King Systems Corporation manufactures a wide variety of face masks, many of which can be seen at www.kingsystems.com.
The anesthesia face masks shown in prior art typically include a domed portion, having a generally cylindrical connector that defines a gas-receiving port. The connector is disposed at the top of the domed portion. The gas-receiving port is sized for receiving the distal end of a breathing circuit or respiratory tube. A torus-shaped air bladder is fixedly coupled to the lower perimetral edge of the face mask. The air bladder is designed for fitting against the face of the patient. The air bladder is formed from a thin flexible plastic material and is large enough, and inflated at a low enough pressure, to have the flexibility to enable the surface of the air bladder to conform to the patient's skin, to create a seal between the air bladder and the patient's skin. By creating this seal, the amount of anesthesia and other gases within the interior of the dome that escapes to atmosphere is reduced. This reduction of gas leakage helps to both ensure that the patient receives the full benefit of the anesthetic and respiratory gases that flow therein, and minimizes the contact between these respiratory and expiratory gases and persons working on the patient, such as doctors, nurses and the like.
Many air bladders include a valve that enables the practitioner to introduce air into, or remove air from the interior of the air bladder, and thereby adjust the air pressure therein, and the amount of conformability that the air bladder can exhibit, when placed adjacent to a patient's face.
One difficulty that is encountered with the use of a face mask is maintaining the face mask on the face of the patient during the procedure, and especially during a long term respiratory event. In order to maintain the face mask on a patient, the current procedure is to employ a ring and strap member configuration.
As best shown in Hellings, U.S. Pat. No. 5,975,079, and some of the web site excerpts discussed above, the ring member typically includes a ring having a central aperture that is sized to interiorly receive the generally cylindrical gas port connector, so that the ring can fit over the cylindrical gas port connector. The ring includes a plurality (usually 4 or 6) radially extending arms that are spaced in intervals around the circumference of the cylindrical part of the ring. An upwardly extending prong is formed on the distal (radially outward most) portion of each of the radially extending arms, and serves as a prong or stud member.
As best shown in FIG. 4 of Hellings '079 patent, and in FIG. 7 of the instant application, the strap typically comprises a heavy elasticized rubber or plastic strap having at least two series of apertures extending along the length of the strap. The middle portion of the strap is placed behind the head of the user, with the ends of the strap being placed adjacent to the dome of the mask. The upwardly extending stud-like prong members that are disposed on the distal ends of the ring are inserted through appropriately positioned apertures of the strap to attach the strap to the mask. Due to the elastic nature of the strap, one can effect a snug engagement of the mask to the user's head by stretching the strap slightly before inserting the prongs through the apertures of the strap, so that the compressive force exerted by the strap holds the mask snugly into engagement of the face of the patient.
Although this strap and ring method performs its intended function in a workman-like manner, room for improvement exists. In particular, the straps of the present kind have some less-than-desirable features that can be improved.
One less than desirable feature relates to the size and bulkiness of the strap. The size and bulkiness of the strap has the potential to create additional clutter around the patient's face that has the potential to impair a surgeons' or nurses' ability to work on the patient. Another undesirable attribute of the strap and ring arrangement used currently is that the straps and ring are relatively expensive to manufacture and purchase, when compared to the strap of the present invention that will be discussed below.
Another less than desirable feature of the strap and ring arrangement of the prior art can best be understood by viewing the series of aperatures in the strap, into which the prong can be inserted. These apertures provide a limited range of incremental adjustability of the size of the strap. Although the plurality of apertures enable the user to effect the size of the strap to a number of different sizes generally equal to the number of apertures in any particular series, the number of incremental adjustments is limited by the number of apertures, Further, the size of the particular increments in which the strap can be adjusted is also limited by the distance between adjacent apertures. This incremental adjustability of the aperture and prong type straps of the prior art, could be improved if a system were devised that would permit infinite adjustability, or at least an adjustability wherein the adjustments could be made in increments smaller than the increments provided by the strap of the prior art.
One object of the present invention is to provide a ring and strap system for maintaining an anesthesia face mask on the head of the user, that is less expensive, and adjustable in smaller increments than the strap and ring system of the prior art discussed above.